Railway car retarder



Feb. 16, 1954 c. w. KUHN RAILWAY CAR RETARDER Filed Jur me 4, 1947 ll ll" Patented Feb. 16, 1954 RAILWAY CAR RETARDER Clarence W. Kuhn, Wauwatosa, Wis., assignor to Cutler-Hammer, Inc., Milwaukee, Wis., a corporation of Delaware Application June 4, 1947, Serial No. 752,307

1 Claim.

This invention relates to railway car retarders, and more particularly to automatic control systems therefor.

It is common practice in railway freight yards to sort or classify freight cars by pushing the cars over one side of an elevation commonly known as the hump and then allowing the same to run by gravity down the opposite side of the hump into selected sidings. The cars usually acquire considerable speed in running over the hump and must be retarded sufficiently when entering the sidings to provide for proper stopping thereof. It is desirable that this retardation be effected automatically, and the present invention has among its objects to provide a simple, reliable and eflicient automatic control system for this purpose.

Another object is to provide an automatic control system of the aforesaid character which operates to subject either a single car or a group of cars to a retarding force which is a function of the weight and speed thereof.

Various other objects and advantages of the invention will hereinafter appear.

The accompanying drawing illustrates an embodiment of the invention which will now be described, it being understood that the embodiment illustrated is susceptible of modification without departing from the spirit and scope of the appended claim.

In the drawing,

Figure l is a schematic view illustrating an automatic car retarder system embodying the invention, and

Fig. 2 is a diagrammatic view illustrating the construction and circuit connections of automatic control. means illustrated generally in Fig. 1.

Referring to Fig. 1, the same illustrates a stretch of railway track I which may constitute the head end of a siding into which cars indicated by reference numeral 2 are run by gravity from a hump in the direction of arrow A.

Track l is provided with a motor operated car car wheels on rail l and the latter pair being arranged for frictional engagement with opposite sides of car wheels on rail l The two pairs of braking bars 6 6 and l -l are operatively connected to a pivoted lever 8 which is operable by a reversible motor 9 to move said bars toward and away from their associated rails for engagement and disengagement with the car wheels thereon. As shown in Fig. 1, motor 9 drives a screw it which carries a traveling nut H and lever B is operatively connected to said nut through the medium of a compression spring 12. Upon operation of motor 9 in a direction to move nut H toward the right out of the extreme position shown in Fig. 1, spring 12 is compressed to operate lever B for movement of braking bars 5 -5 and I -4 toward their associated rails l and l into position for braking of the car wheels. As is apparent, the braking effect of said bars upon the car wheels is determined by the degree of compression of spring ['22. Upon return of nut II to the extreme position shown in Fig. 1 spring I2 is released to permit movement of braking bars B -B and l 'l away from their associated rails into non-braking positions.

Motor 9 may be of a direct current type and as illustrated in Fig. 1 a pair of electromagnetic reversing switches l4 and I5 are provided for selectively establishing forward and reverse power connections therefor from a direct current supply circuit indicated by lines L L Also as illustrated in Fig. l a pair of limit switches l6 and I1 are associated with nut I l and as hereinafter set forth said limit switches provide for control of switches I 4 and [5 to effect stopping of motor 9 in extreme brake releasing and brake setting positions.

As hereinbefore stated, car retarder 3 is automatically controlled by a controller 4 associated with a car weighing device 5. As shown in Fig. 2, controller 4 includes a normally open switch l8 for controlling switch It, a normally open electromagnetic relay [9 for controlling switch it and control means for said relay including a step by step control switch 20, an adjustable rheostat 2| and a plurality of condensers 22, 23, 24 and 25. I

Switch 2 includes a pair of movable contact segments 26 and M which cooperate with a plurality of stationary contacts 28 to 33, inclusive. The movable contact segments are mounted upon a rotatable ratchet wheel 34 which is normally held by a spring 35 in the position shown in Fig. 2 for bridging of stationary contacts 23 and 29 by contact segment 25 and bridging of stationary contacts 38, 3 l, 32 and 33 by contact segment 2?. Ratchet wheel 34 has a reciprocable operating pawl 36 associated therewith for ef-' fecting step by step operation thereof in a counterclockwise direction out of the position shown in Fig. 2. Also ratchet wheel 34 has a normally released latch 31 associated therewith which is movable by a magnet 38 into a position to lock said wheel against rotation in a clockwise direction.

Pawl 35,, switch 18, and rheostat 21 are provided with a common operating element 40 which is associated with the load weighing device 5. As illustrated in Fig. 2, the load weighing device comprises an I-beam 4! which is supported. at opposite ends within a pit 42 by stationary abutments 43. One of the rails of track I', as for example rail l is supported upon the upper side of I-beam 4i and said I-beam is made of sufficient length to extend between opposite ends of a. car. Operating element 4!! is operatively connected to I-beam 4! through the medium of a pivoted lever 44. As hereinafter set forth, upon movement of a car: onto. the rail s c-tion supported by I-beam il said Ie eem is deflected downwardl out of a iven normal posi ion. to eff ct closure of switch. I82. adv nce. of: switch 20 y pawl. 36. and setting. of rheostait. 2i in. a; po ition correspondin to the wei ht of said; car.

The operation of: the aforedescribed car ret-arder system. will. now be more fully described.

Assuming that a single car, as for example the car 2 of Fig. l, coasts in the, direction oi arrow across the; rail section supported by I-beam 4 I. Said; I-heam will be flexed downwardly away from the normal position shown in Fig. 2. first. by the. weight on. the front. wheels of. the ear and. heir by the Weight on, the rear wheels thereof. Switch it. closes immediately upon downward movement of. I-heam. cl, out of norm l. position and upon closure of. said switch the operating winding of switch. Ul is. connected across lines L L throughthe. medium of. limit; switch ti switch Ht then responds to. energize motor. 9. for operation in a direction to move. nut- II toward he for compression of prin 12. During the time required ior movement. of. the car across the rail section on lZ-beam. M; nut H. is moved; into its. extreme right: hand. position to maintain brake bars: !i 6. and l l in. set position. by the. iuil operating force. of. spring 42. Limit. switch. ti: isv openedupon. movement oi not It into its extreme right, hand. position ind-dropout; switch is for stopping of motor 9.-

It will. he noted that. upon movement or the. front wheels; of. car i into a po ition. midway be. tween the ends of I-beam M said Irheam will be flexed; downwardly out; or normal. position. to a degree: determined by the weight on said Wheel and; upon movement of the front car wheels be;- yond; thi position, said I-beam returns toward normal position. However. prior to full return of the. I.-beam toward normal position the rear. Car. wheelsmove intoa position midway between the ends; of said; I-beam, to again effect downward fiexure thereof, this time to a degree determined by the weight on said rear wheels. These two downward, flexures; of I.-beam. ll efiect operation of; switch. 2.6 by itsassociated pawl, 1'6. from. off position into the position. marked a and then into theposition. marked b. During movement of carv 2 into a position, wherein the front and rear wheels thereof span the.- lever 44- switch It is maintained in closed. position by downward flex;- ure; of I-beam 41:. Zaacmss I-be-am 4i magnet 38 is connected across lines L L? by switch It to maintain latch 3! in Iocking, position and. thereby prevent return. of.

Thus during movement of car switch 20 to off position under the action of its associated spring 35.

Upon movement of switch 20 into the positions marked a and b condenser 22 is connected across lines L L through the medium of switch l8, rheostat 2|, switch contacts 26 and 29 and an adjustable resistance 22 As is apparent, during travel of the car across. the rail section on I-beam M the control arm of rheostat 2| is moved in a counterclockwise direction out of the normal position shown in Fig. 2 to a degree determined. by the weight of the car. Condenser 22 thus receives a charge the value of which is determined by the setting of rheostat 2| under the action of the weight of the car and by the time required for movement thereof across the rail section on I-beam 4|. If the car is heavy and travels at high speed condenser 22 receives a minimum charge. On the other hand, if the car is light and travels at slow speed condenser 22' receives a, heavy charge.

Upon movement of the car beyond the rail section on I-beam n said I-beam returns to normal, position and opens switch. I8 for deenergization. of. magnet 38. Latch 31 is then releasedand. switch 29 returns to the off position shown Fig. 2' under the action of its associated spring 35. The. operating winding of relay I9 is now connected across condenser 22. in series with a regulating resistance 46 through the medium of stationary contacts 28 and; 29 and movable contact 23 of switch 20. Condenser 22 then discharges through, the operating winding of relay I9, to effect response of. said relay for a period determined by the value of the charge in said condenser. Upon closure of relay 19. the. operating winding of reversing switch I5 is. connected across. lines Li -13 through the medium of limit switch [6 and upon response of said re.- versing switch motor 9 is energized for operation in a direction, to move nut. ll away from its extreme right hand position.

If the car is heavy and traveling at high speed the charge in condenser 22 may be insufiicient to effect response of relay l9 upon return of switch 20 to off position. Under this condition nut l l remains in its extreme.- right hand position for setting of brake bars 6 and l -l by the full operating pressure of spring l2 to provide for maximum retardation of the car during, coasting; thereof across retarder device 3'. 0n the other hand, if, the car is light. and traveling at a relatively slow speed they charge in condenser 22 will be of such value that upon return of switch; 20.: to. off position relay i=9 responds and. remains in A closed position to maintain motor 9 energized for a. period sufficiently long to provide for movement of nut I I into its extreme left hand position. Motor 9 is. then deenergized by opening of. limit switch It and the brake bars E -6 and I -1 are relieved from the-setting pressure of spring 12 to thereby provide for coasting of the car across the retarder device 3 without substantial retardation. As is apparent from the foregoing, if the car is heavy and: travels at a low speed, or if the same. is light and travels; at a high speed condenser 22 is charged to a degree to maintain relay [9 in closedposition for a period which. Provides for movement of nut H out of its extreme right hand position into an intermediate position. The setting pressure of spring t2 on brake bars 6 6 and 1 1b is thus reduced toprovide for proper retardation of the car, under these con.- ditions.

Assume now that additional cars. 2 and 2 are coupled to car 2**, and that these cars move in the direction of arrow A across the load weighing device 5. During movement of car 2 across load weighing device 5 the controller will operate as hereinbefore set forth to move nut ll into its extreme right hand position for setting of brake bars 6, 6 and 1 1 by the full operating force of spring l2 and to also move switch 20 from ofi position into positions a, and b for charging of condenser 22. Switch I8 is held in closed position during movement of the several cars across load weighing device 5 to thereby maintain the energizing circuit for holding magnet 38 and to also maintain the charging circuit through rheostat 2|. During movement of car 2 across load weighing device 5 rheostat 2| is moved into positions determined by the weight on the front and rear wheels of said car and switch 2|] is advanced into position and then into position (1 to connect condenser 23 in parallel with condenser 22. Also during movement of car 2 across load weighing device rheostat 2| is moved into positions determined by the weight on the front and rear wheels of said car and switch 20 is advanced into position e and then into position to connect condenser 24 in parallel with condensers 22 and 23.

Thus during travel of cars 2, 2 and 2 across load weighing device 5 each of the condensers 22, 23 and 24 receives a charge the value of which is determined by the speed of said cars and the average weight thereof. Upon movement of car 2 off of the rail section on I-beam 4| of load weighing device 5, switch 18 returns to open position to deenergize magnet 38 for release of latch 3! and to interrupt the charging circuit through rheostat 2|. Upon release of latch 31 switch 20 returns to the normal position shown in Fig. 2 to connect the operating winding of relay l9 across condenser 22 in series with resistance 46 and said relay then responds to maintain switch energized for a period determined by the charge in condenser 22. Motor 9 is thus energized to move nut I I toward the left away from its extreme right hand position to a degree determined by the speed of cars 2, 2 and 2 and the average weight thereof so that spring I: is adjusted for proper retardation of said cars by braking bars 6 -6 and I -1 Also upon return of switch to normal position contacts 30, 3| and 33 are bridged by contact segment 21 to connect condensers 23 and 24 for discharge through a resistance 41.

In the embodiment illustrated in Fig. 2 switch 20 is movable into positions 9 and h to provide for charging of a condenser 25 if a fourth car is included in the car group illustrated in Fig. 1. As will be understood, the distance between load weighing device 5 and car retarder 3 must be such that when the last car of a group travels over the load weighing device 5 suflicient time is obtained to permit setting of car retarder 3 before the first car of the group moves on to said retarder.

As illustrated in Fig. 2, each of the condensers 22, 23, 24 and 25 has an adjustable resistance a connected in series therewith for regulating the rate at which said condensers are charged during the aforedescribed operation of the controller. The adjustable resistance 46 which is connected in series with the operating winding of relay l9 provides for regulation of the period during which said relay is maintained in closed position in response to a given charge in condenser 22.

What I claim as new and desire to secure by Letters Patent is:

In a railway car retarder system, the combination with a retarder associated with. a railway track for effecting retardation of a car traveling thereon by frictional engagement with the car wheels, said retarder having power adjusting means associated therewith for varying the retarding effect thereof, of a car weighing device associated with said track over which the cars travel prior to arrival thereof at said retarder, means rendered operative upon movement of a car onto said load weighing device for controlling said power adjusting means to efiect setting of said retarder in a position for maximum retardation, a condenser, means for charging said condenser during travel of a car across the load weighing device to a value determined by the weight of the car and the time required for travel across said load weighing device, and means subjected to control by the charge in said condenser upon movement of the car beyond said load weighing device to control said power adjusting means for release of said retarder to a degree determined by the charge in said condenser.

CLARENCE W. KUI-IN.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 1,626,920 Coleman May 3, 1927 2,061,753 Bone Nov. 24, 1936 

